Amplification of glyceryl trinitrate-induced headache features by noxious craniofacial stimuli in pain-free healthy humans.

Aim: Glyceryl trinitrate (GTN) provokes an immediate migraine-like headache, followed by a delayed migraine attack in migraineurs. In healthy volunteers, only an immediate, less severe and shorter headache occurs. The presence of an already sensitized nervous system in migraineurs may underlie the more intense and prolonged GTN-evoked headaches.